Soluble copolymers of diallylic phthalates and allylic alcohols



Patented Sept 30, 1952 SOLUBLE COPOLYMERS OF DIALLYLIC PHTHALATES AND ALLYLIC ALCOHOLS Pliny 0. Tawney, Passaic, N. J assignorto United States Rubber Company, New York, N. Y., a corporation ofNew Jersey No Drawing.

Application September 12, 1945, Serial No. 615,927

6 Claims. (01. 260-783) My invention comprises a method for preparing a new class of unsaturated polymeric materials of relatively low molecular weight which are soluble --in a variety of organic liquids, but which areconvertible to insoluble, infusible resins in the presence of heat and/or catalysts, by further polymerization or by copolymerization with reactive compounds containing an ethylenic linkage. More particularly, my invention relates to unsaturated, polymeric materials derived from a diallylic phthalate.

It is well-known that the polymerization of a, 'di'allylic phthalate leads to theformation of an insoluble gel after a relatively small amount of the monomer has been converted to the polymeric form. The resulting mixture, which consists of a minor proportion'of insoluble, infusible polymeric diallylic phthalate suspended in and swollen by a major proportion of unreacted monomeric diallylic phthalate together with a small amount of low molecular weight polymer, is exceedingly difiicult to manipulate -'in various processing operations and is practically-devoid of commercial utility. Forexample, its use in coating compositions is severely restricted by its inability to dissolve completely inorganic solvents, and even when applied directly, 1. e., in the absence of solvents, the resulting films are weak, uneven, non-uniform and unattractive because of the presence of lumps of gelled polymer. Bimilarly when the mixture is cast in bulk by heating in a mold with additional catalyst until furpartially polymerized diallylic phthalate admixed with a much larger proportion of unreacted monomer which must be'laboriously isolated and recycled for use in subsequent polymerizations. The polymer'itself must be purified by dissolving it in a solvent and reprecipitating it with a nonsolvent. Obviously such a procedure is both expensive and time-consuming.

The proposed uses of reaction temperatures above 180 C. and/or large amounts of catalyst as recommended in U. S. Patent No. 2,273,891 and U. S. Patent No. 2,339,058 as a means of increasing the yield of soluble polymer prior to gelation. Eowever, in practice it is necessary to carry out a very careful and complete separation of these inhibitors from the polymeric product to avoid discoloration thereof as well as retardation .or

'ther polymerization occurs, the resulting castings complete inhibition of its subsequent conversion to the insoluble infusible state. On a commercial scale this separation is particularly laborious and I time-consuming and adds to the overall cost of the product.

The above-mentioned patents also propose to carry out the polymerization of diallylic phthalates in the presence of solvents, in orderto improve the yield of ungelled polymer. However, this method requires the use of relatively large amounts of solvents which is disadvantageous since the rate of polymerization tends to decrease in dilute solution, particularly when conducted only at the low reaction temperatures attainable by refluxing solutions of. the diallylic .phthalate in the low-boiling solvents commonl'y'employed,

e. g., acetone, carbon tetrachloride,etc. Furthermore, polydiallylic phthalates prepared in carbon tetrachloride solution, as described in U. S.

in aqueous emulsions as mentioned in U". S. Patwith a readily homopolymerizable monomer leads rapidlytothe formation of an insoluble crosslinked product before more than a very minor amount of the diallylic phthalate has'become incorporated in the copolymer. This is indicated ble. cross-linked products. ester groups'will also undergoalcohol interchange 2 diate commercial interest.

by Garvey and Alexander in U. S. Patent No.

1 2,202,846. Hence, the copolymerization of dial- I have now unexpectedly discovered that by polymerizing a mixture of diallylic phthalic. with a monomer which itself possesses little' tendency to homopolymerize, specifically an allylic alcohol from the class consisting of allyl alcohoLbetae, alkylallyl alcohols, and gamma-alk-ylallyl aloe-1 hols, high yields of a soluble, fusible, unsaturated copolymer can be obtained. In further contrast to the prior art, the preparation of my new copolymers, by which the major proportion of a monomeric diallylic phthalate can be converted to the polymeric form without insolubilization,

doeslnot require the presence of inhibitors; o'riof any solvents other than the copolymerizable monomersithemselves.

The copolymerizable allylicelcohdls employed inimy' invention have proven'remarkably efiident: in repressing gelation even when they are presentin the reaction'mixturein relativelysmall amounts-L Imaddition to their manifest. utility, my new co' iiolymers are unique in regard to. their chemi cal structure since asoluble, fusible unsaturated copolymer 015a diallylic phthalate and an allylic alcohol appears unknownsin the prior art.

That my products are true copolymers is provenbyelementary analysis and other specific tests They contain attached. to the polymer chain 'unsaturated ester groups which can be polymerized to. convert the copolymers: to insolu- These unsaturated reactions with other saturated. and unsaturated alcohols. My'products also contain alcoholichydroxyli' groups in' theform of: side-chain hydroxymethyl groups which-permit modification of the copolymers" by agents known to react with alcof hols, such agents including alkyl, allylic. and acyl "halides; organic acids and their: anhydrides; or-

ganic iso'cyanates andisothiocyanates" as well as thecorresponding poly-functional compounds such: as the dihalides, dlisocyanates, poly-carboxylic-acids etc Thus lhave'succeeded in producing anew and useful: class of soluble convertible resins. derived from a diallylic phthalate" which are obtained easily and in such high yields as to be of imme- In contrast. to the prior art. I can convert the major proportion of az'm'onom'eric diallylicphthalate to the polymeric form-without insolubilization. The copolymerization reaction, which requires only relatively small amounts of catalyst, proceeds smoothly at moderate: .;temper'atures; ,,and can be economically conducted in. conventional and readily available reaction vessels without the need for special reaction conditions or other precautions to avert prematureagelation. The resulting soluble unsaturated copolymers which-are obtained in high yieldsare uniform in character since they are uncontaminated with the high molecular weight insoluble gel encountered in many of the prior artpolymers of diallylic phthalates, and hence the necessity for extensive purification is obviated. My new copolymers totally dissolve in a number of common organic solvents and they curei rapidly and completely to the insoluble, in-

fusible state with little or no discoloration even when heated as high as 200 C. This combination of attributes makesmy products Well suited to the formation of coating compositions, particularly baking varnishes and white enamels.

Of the diallylic phthalates usefulin preparing my new copolymers, I preferv diallyl phthalate and dimethaliyl phthalate. Among the operable alcohols, allyl alcohol and methallyl alcohol, both of which are readily available, have proven satisfactory although other beta or gamma-substituted allyl alcohols, such as 2-ethylallyl and 3- methylallylalcoholare also useful in my invention; In. general,;, the copolymerization of an allylic: alcohol with: the phthalic ester of a diiferent allylic alcohol e. g., methallyl alcohol or crotylalcohol, (i; e'., gamma-methyallyl alcohol) with diallyl phthalate, tends to give the maximum yield of copolymeric product.

The relative proportions of the allylic alcohol and the diallylic phthalate can be varied over a considerable range depending upon thephysical properties and the amount of hydroxyl groups desired in' the resulting product. Copolymeriza tion of the diallylic phthalate with as littleas approximately 10% of the allylicalcohol (based on the weight of the diallylic phthalate) is sulficient to repress the gelation of the reaction mix;- ture during the early stages of the copolymeriza tion and to insure an increased yield of soluble unsaturated product. The higher the amount of copolymerizable allylic alcohol present, the higher the'amountvof the monomeric diallylic phthalate which can be converted to the copolymeric form without insolubilization. Optimum yields of the soluble products are obtained when thenamount of the allylic alcohol is inthe neighborhood of by weight of the diallylic phthalate, Since my copolymers are readily soluble in allylic al cohols, the copolymerizations may be carried out in the presence of still higher amounts, say up to 200%, of the allylic alcohol, if desired, for the resulting -mobile, free-flowing solutions have-desirably low viscositiesand are easily handled in transfer, mixing, storageand other mechanical operations to which. the solid copolymers. themselves may be less amenable. In such cases the allylic alcohol: serves in the dualrole of a 00.- polymerizable monomer anda cheap volatilelsolvent which, because it possesses little tendency to homopolymerize under these conditions, can be easily removed from the: reaction mixture by dis;- tillation and recovered for use in subsequent co polymerizations. r

In the preparation of my newcopolymersthe reaction temperatures may range from about 25 C. up to and somewhat above the boiling point of: the allylic alcohol, and for overalleconomy it ispreferred to operate in the latter range, i. e., atthe reflux temperature of the reactionmixture..- Higher temperatures can of course be employed but the necessary pressureequipment entails additional expense without. ofieringf any marked compensating advantages. Suitable polymerization catalysts include hydrogen peroxide, acetyl peroxide, benzoyl peroxide, acetyl benzoyl peroxide,-su ocinyl peroxide and tertiarybutyl hydrogenperoxide, The course of the copolymerization can be followed by observingthe increase-in viscosity of the reactionmixture and after halting the reaction by cooling, the copolymer can be readily-isolated from the reaction mixture by distilling. off any unreact ed starting materials or by" extracting them with a. s.olver;iti n which the copolym'erris.insoluble,jsuch it isunnecessary to isolate the copolymer as is I done in the prior art, for the higher-boiling solvents'can be added directly to the crude copolymerization reaction mixture and any .unreacted allylic alcohol can be then removed'by distillat ion. This effects a further saving in both the time and" expense of the process, and adds to the economic advantage of my copolymers.

6 starred in Table I below which still-show no signs of'gelation after heating for the :times inadicated. The reactionsiare then halted'by cooling and'the reactiommixtu'res are poured into gasoline. The precipitated materials: are further purified by dissolving'them in. chloroform, and precipitating them with gasolineafter which they are dried to constant weight in'vacuo and the yields'determined. v

The pertinent datalare summarizedbelow in Table I including the weights of the .copolymerizable I monomers, peroxide and" polymeric product, as well as the reactionzltimes. For purposes of comparison only, the polymerization of a diallylic phthalate in the absence of an allylic alcohol. (1-11 and -d) and also inthe presence of solvents (I-k and -Z) are included to illustrate more'fully the advantage "of the copolymers of my invention.

Table I Di- Reaction Diallyl Allyl Methallyl Crotyl 1 methallyl Peroxide Time Yield Phthalate Phthalate Alcohol Alcohol Alcohol (mu-rs) I 5.50 "Q 15.0 42. v 8.75 7 cm 62. 3. 79 160. 0" 54. v0. 311- 11.0 '28. .0.830 16.0. 45. 0.934 26. 0 57. 1. 040 52.:0 j 59. Y 23. 60v 4.96 ,22. 0* 82. p 28:80 '8.300 20.0 89. 5.17 65.0", 63. 29.2 parts of ciadrbon tetrachlo- 2.48 4.75 76. 100.0 parts of benzene 0. 821 52.5 :50.

I *Nosign otincipient gelationw .Application ofv heat to compositions contain- .ingmyunsaturated copolymers, particularly in thepresence of catalysts,-inducesfurther poly merization and. the resulting cross-linked products arequite indifferent to heatand are strongly :resistantto attack by solvents. Suitable dyes, pigments, fillers, plasticizers and resins can:be in orpora ed. hi y opol m in th olubl fusible. stage-prior to final cure.

' y. o ublelsuns tu at d y fs t t. ls

beg-converted to the insoluble, iniusible state by interpolymerization W1, h :reactive mpnomers containing an ethylenic linkage, 'e. g., methyl acrylate, 'Vinyl acetate,'diethyl fumarate, allyl ae ylata ia lu a j a. M. h so u tage my ,copo e s d sso ve eedilyi 'a number oi these reactive monomersto yiel d soluns which o te quite flu veaat h h solids content Such solutions a can be totally jfallylicalcohols. are heated with teitiar'y-butyl fhydrogen' peroxide'160% solution); a "catalyst at 120 CLin sealed Vessels until the poi tior ini cipientj gelationds', attained save in: the, cases v I v y- JQI dl i g ors l e t b e a o ate and are useful not only as coatingcompo sitions,

. l. iv us'prop'ortions of diallylic phthalates and The analysis corresponds to. a copolyrne I Comparison of 1-11 with 1-6 of'the above 'table illustrates theefie ctof copolymerizing even small amounts of an allylic alcohol witha diallylic phthal'ate' in repressing j'gelation and increasing the yield of solubleunsaturatedjpolym'eric product, while 1-), g; hand i show'that the-yield-of soluble copolymer increases with the presence of increasing arhountsof theeopelymenzame allylic alcohol in the initial'mixture of reactants. A

comparison of I-lc'and 1-1 with L-horI i demenstratesthe greater efiicien'cy of the cop'olyinerizable allylic alcohol (as comparedwithine'rt nonfiole'finic solvents) in repressing: gelatlcn'and increasing the yieldof soluble polymeric .matrm.

Example l ishows that my discovery includes 'not only the allyl and beta alkylallyl "alcohols hutthe "gamma-alkylallyl alcoholsas well.

A mixture of 246.0 parts of diallyl phthalate, 58.0 parts of allyl alcohol and 12 parts of a 60% solutionof tertiary-butyl hydrogen peroxide is refluxedwfor lofi hours, An aliquot pf seventytwo and five-tenths parts of the clear 'scous reaction mixture i s withdrawn and DQ Ied-intp gasoline.- The precipitated product is further purified by repeated solution in chlorotormand precipitation with gasoline. v v Y aQhlOftO constant-weight, 31.0 parts ofpolymeric solid are obtained. This corresponds to;a total: yield ofapproximately 134 parts, pflthe- After, drying- .in

copolymer. 1

Iodine number (Wijs) 60.7.

tainingl approximately 82.2% by weight o lumnae a 1. 0 l a aken.

1 mor si hours "at 95 'todinesnuniber': or. the eopolymer indicates;- :the presencei'oiiz'unsaturationiderived from; the interphlymeiiizedf dia-"llyii phthalate units""while the presence-of; interpolymerized allyl: alcohol units ishneqnivocably demonstratedyby treating; the copolymen'with a hydroxyl reactiveragent-,7 i. e;,. antisocyanate; as follows.

- Ten-"parts: ofr'the-purified; copolymer are dissolved in 50 ml. of pure anhydrous pyridine and a I aftenaddingto the solution 6:1 parts of phenyl iso'cyanate; the mixture is heated in a sealed tube: for'19 hours at 90' C. The majority of the pyridinaxand" any unreacted phenyl. isocya'nate areith'em removed-i from; the reaction mixture. by evacuatiorr'atvroom temperature and the syrupy residue ispoured into 200 ml. of gasoline." The the polymeric urethane is dried in vacuo to constant weight: w

Analysis.-Found: N, 2.15% r conolymerrin acetonezhasra-viseosity or (L85- poise air- Ci .TlIa-copolymer itself-is compatible withz. a.:dryi=ng:-oi1=-modified alkyd resin prepared bpreactingr ieu-warts: of refined linseed oil, 95 parts of glycerine, 424parts of diethylene glycol and 490.;parts of maleic: anhydride until thereactiom product has: an acidnurnber of 61.0..

Another-sampled the xylene solution of the copolymer is diluted with 20%. by weight. pi. xylene andflowed-onto a glass: panel. After bakingfor ZO- minutes at 200? C. a. elear, solvent.- andeheateresistant' film. is obtained. Very little discoloration-occurswhen the'filmis baked-.at 2.00. 1 0;. for" an additional 401 minutes. in. con.- traslz; awfilm of Ediall-yl. phthalate polymer, which had.- been polymerized in the presence. ofcarbon tetrachloride: according to a method; shown. in U. SiBat'ent No- 2.339.958 and: bakedon; alas-sis discoloredandydisintegrates; upon contact; with acetone. A similar film of diallyl phthalate polymer when baked on a steel panel became coal-black and opaque, whereas a film of polymer. made according to my invention and baked polymer. clearly demonstrates that the. original H product must contain free hydroxyl groups'whi'ch' Q are of course reactive to phenylisocyanate, forms-7 his a polymericphenyl urethane; Y m a. From the crude polymerization reactionr mixture' above an aliquot'of 100.0 partsfis' withcrrawn'and admixed with 10.3 parts ofmonomeri'c 'di ethyl fumarate.

A trace of hydroquinone is added to inhibit premature 'copolymerization or the monomer'with the 'copolymer and the mixture is distilled at'90 C. and 3 mm. for 1.5 hours dur--' I jtack free at 120 CL and-isresistant to attaok by reeni q e i 1* the manner of. (a) above.-2?; .3; parts of the; crude; reaction mixture are admixed with 3.7 :partsof diallylfumarate; threean'd seventenths -partsofqallyl alcohol are distilledaou-t,

and then 0.25; part of benzoyl peroxide/is added and-the solution heated in atmold at 60P5 o. for

The'presenceof 'nitrogenin this modified co 25- on a-steel: panel is transparent and shows but little discoloration.

' EXAIMPLE 4 Two-hundred and forty-six parts of diallyl phthalate are admixed with 108 parts of methallylalcohol and l5.3 parts of a solution of tertiary-butyl hydrogen peroxide and heated at reflux iorlii'hours. From the viscous reaction mixture, an aliquot of 11.2 parts is withdrawn and poured into gasoline. The precipitated cojfpolymer i's further purified by repeated solution 12 hours and thenyat 120 (Liar; 2 additional hours to form a clear hard'casting which is insoluble in organic" uinfusiblen 1 mmature e 492;- parts of aianyr'phthalate. parts-er allyl alchol-andfl'parts of a 30% eous -"solu tion of hydrogen peroxide is heated he' reaction mixture is unutea witn oe part c or xylene an heated at approximately '30? G. and 3- mm. until eso'parts or "'al x'y'lene ally; alcohol mixture have distilled out. Two -hundred more' parts of 1 xylene are- -then added andheating"continueduntil 186 additional parts of distillate are collected. From tl-ie res idual solution of the eopolymer in xylene analiquot of 17.6 parts is withdrawn and poured into an excess of gasoline. f l he precipitatedeopolymer is further purified by solution in chloroform and solvents and substantially in chloroform and precipitation with gasoline. After drying in vacuo', 6.05 parts of. polymeric solid are obtained This corresponds to a;.1tota1 yield of approximately 198 parts of copolymer.

I One hundred'parts ofthe crudereaction mixtur'e are admixed with 15.0 parts of diethyl fumarate and evaporated.- at 25* Ci and 1' mm; until distillation ceases. The residual solution is cooled and after addition of 2.0 parts-of benzoyl peroxide, a sample iscured in a plate mold by heating for' 23 hours at 70 C. andthen for- 2 hours at C. The resulting transparent sheet is hard, tough and resistant to heat and solvents;

- I Amixture-of 'parts of niethaHyI alcohol-and 24.8 partsof 9. 60% solution of tertiary-butyh hydrogen peroxide is heated at refiux for25-hours. Eleven and thirty- "fi-y'e hundredths parts of the 'crude reaction mixhire-are withdrawn and pouredinto gasoline. hireprecipitated cop olymeris -further' purified by frepeated solu'tioriin chloroform and precipitation 'witnga e me: Aftr drying in vacuo, 6.23 "parts or polymeric solid are obtained which corresponds to a total yield orapproximatemnro parts *of-" they eopeiymerg 70 j'solution of the copolymer -m" acetone hasa 'yi'scosit'y of l5.2"-poise's at 4 q. The remainder of the crude reaction mix- 'ture-ji's diluted with atotal 015;;300 m1. of ylene and'heated at approximately '35 c; and 4 mm. 'i fl i'p rts Qf a. mixture-of xylene anemiaally-alcohol hasdistillecl'out. resulting. "solution" of the 'copolym er' in xyleneiis A v sample of the "diluted -with 25 by weight of acetoneandflowed -3onto;a{giass* panel. After baking at '200" c.- for "precipitation with? gasoline! -After='"dryingt-m --parts of a whitepolymeric; vselitr'are l'zmmmiie r et er-films bt ined which shows I I H I I I excellentresistance-toattack by acetone." A "29% solution (by weightrmr tire -7 'bi The tolerance ofthe' copolymerfoi 'arolnatjic 492 p rts of dam amuse,-

solvents is demonstrated by diluting another sample of the above xylene solution with additional xylene until the solvent constitutes 3300% of the dissolved solids. The resulting solution is still clear and homogeneous.

EXAMPLE 6 ber of 4.5, and 4.58 parts of the varnish are admixed with 2.75 parts of xylene containing dissolved therein 0.00182 part of manganese naphthenate. The mixture is flow-ed onto a glass ,panel and baked for 1 hour at 150 C. to yield a clear, tough acetone-resistant film.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. An acetone-soluble, fusible copolymer of a binary mixture of monomers consisting solely of a diallylic phthalate monomer selected from the class consisting of diallyl phthalate, and dimethallyl phthalate monomers and an allylic alcohol monomer in which the allylic radical is selected from the class consisting of allyl, betaalkylallyl, and gamma-alkylallyl radicals, said copolymer containing residual unsaturation and being capable of further polymerization.

2. An acetone-soluble, fusible copolymer of a binary mixture of monomers consisting solely of diallyl phthalate and allyl alcohol, said copolymer containing residual unsaturation and being capable of further polymerization.

3. An acetone-soluble, fusible copolymer of a binary mixture of monomers consisting solely of diallyl phthalate and methallyl alcohoL-saidcopolymer containing residual unsaturatiqn and being capable of further polymerization.

4. A process which comprises polymerizing by 10 heat with the aid of a peroxy catalyst a mixture of monomers consisting solely of a monomeric diallylic phthalate selected from the class consisting of diallyl phthalate, and dimethallyl phthalate monomers and a monomeric allylic alcohol in which the'allylic radical is selected from the class consisting of allyl; -beta-alkylallyl, and gamma-alkylallyl radicals, the proportion of the alcohol being at'least 10% of the weight of the phthalate, to a point short of incipient gelation, whereby to form an acetone-solublafusible unsaturated copolymer of the said diallylic phthalate'and the said allylic alcohol.

5. A process which comprises polymerizing by heat with the aid of aperoxy catalyst a mixture of monomers consisting solely of diallyl phthalate and allyl alcohol, the proportion ofv the alcohol being at least 10% of the weight of the phthalate, to a point short of incipient gelation, whereby to form an acetone-soluble, fusible unsaturated copolymer of the diallyl phthalate and the allyl alcohol.

6. A process which comprises polymerizin with the aid of a peroxyv catalyst a mixture of monomers consisting solely of diallyl phthalate and methallyl alcohol, the proportion of the alcohol' being at least 10% of the weight of the phthalate, for a period less than required for separation of a gelled product whereby to form an acetone-soluble, fusible unsaturated copolymer of the diallyl phthalate and the methallyl alcohol.

- PLINY vO. TAWNEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,332,900 DAlelio Oct. 26, 1943 2,378,195 DAlelio June 12, 1945 2,378,197 D'Alelio "June 12, 1945 2,441,516 Snyder May 11, 1948 2,504,052 .Snyder Apr. 11, 1950 FOREIGN PATENTS Number Country Date Great Britain Dec. 27, 1944 

1. AN ACETONE-SOLUBLE, FUSIBLE COPOLYMER OF A BINARY MIXTURE OF MONOMERS CONSISTING SOLELY OF A DIALYLIC PHTHALATE MONOMER SELECTED FROM THE CLASS CONSISTING OF DIALLYL PHTHALATE, AND DIMETHALLYL PHTHALATE MONOMERS AND AN ALLYLIC ALCOHOL MONOMER IN WHICH THE ALLYLIC RADICAL IS SELECTED FROM THE CLASS CONSISTING OF ALLYL, BETAALKYLALLYL, AND GAMMA-ALKYLALLYL RADICALS, SID COPOLYMER CONTAINING RESIDUAL UNSATURATION AND BEING CAPABLE OF FURTHER POLYMERIZATION. 